Nuclear accumulation of c-myc mRNA in phytohaemagglutinin-activated T lymphocytes treated with anti-HLA class I monoclonal antibody.
Anti-HLA class I monoclonal antibody 01.65 inhibits the proliferative response of PHA-activated human T lymphocytes from peripheral blood mononuclear cells. The recruitment rate in the cell cycle is slack and the G1 and S phases are prolonged. Among the early events after PHA activation, only the calcium-dependent PKC activity appears to be modified: particulate PKC is completely depleted while cytosolic residual PKC is reduced by 80% after MAb 01.65 treatment. We have carried out in greater detail the study of c-myc gene regulation by MAb 01.65 and the results are as follows: (i) c-myc RNA transcription is normally initiated and finished, suggesting a post-transcriptional regulation of c-myc gene expression; (ii) no alteration in c-myc mRNA stability has been documented; (iii) steady-state levels of c-myc mRNA expression by Northern blot analysis and PCR amplification are decreased in the cytoplasmic compartment, while in the nuclear compartment they appear to be increased. Nuclear accumulation of mature mRNA after MAb 01.65 and PKC inhibitor (H7 and StSp) treatment appears to be the most probable mechanism involved. The possible implications of this are discussed.
Selvatici
R
R
Department of Experimental and Diagnostic Medicine, University of Ferrara, Italy. vn6@ifeuniv.unife.it
Boninsegna
S
S
Ferrati
M
M
Gandini
E
E
D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D017931:DNA Primers; D005091:Exons; D016259:Genes, myc; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins; D016133:Polymerase Chain Reaction; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D014158:Transcription, Genetic
D000911:Antibodies, Monoclonal; D017931:DNA Primers; D015395:Histocompatibility Antigens Class I; D010835:Phytohemagglutinins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger